Pennsylvania Sen. John Fetterman took fresh aim at New York City Democratic socialist Mayor Zohran Mamdani on Sunday, branding him a "clown" over his repeated interest in having Israeli Prime Minister Benjamin Netanyahu arrested if he visits New York for the United Nations General Assembly this September."[He's] such a tough guy to say that kind of thing. He has no way to do that," Fetterman said on "Sunday Morning Futures.""America's not even part of that corrupt court," he continued, referring to the International Criminal Court (ICC), which has issued an arrest warrant for Netanyahu.FETTERMAN WARNS MAMDANI RISKS 'CONSTITUTIONAL CRISIS' BY VOWING TO DEFY SCOTUS IMMIGRATION RULING"He's [Mamdani is] just a clown to even say that, so he won't try that. Just sit down and focus on other... problems that they have in New York. That's really not your purview. You and I know that. Sit down."Mamdani has repeatedly said he would seek to have Netanyahu arrested if the Israeli leader travels to New York City, citing the International Criminal Court's November 2024 arrest warrant accusing Netanyahu of war crimes and crimes against humanity stemming from Israel's war against Hamas.Most recently, the far-left mayor said his administration is actively exploring whether the city has the legal authority to arrest Netanyahu, calling him a "war criminal" who "belongs in The Hague," during an interview with The New York Times.Netanyahu has denied the allegations, and Israel rejects the ICC's jurisdiction over the matter.SEN JOHN FETTERMAN PLEDGES TO BE 'LAST MAN STANDING' IN THE DEMOCRATIC PARTY IN SUPPORT OF ISRAELThe United States is not a party to the Rome Statute that established the ICC and does not recognize the court's jurisdiction over U.S. citizens or Israeli officials.Fox News Digital previously reached out to the mayor's office asking whether Mamdani stands by calling Netanyahu a "war criminal," whether City Hall is actively consulting with the Law Department regarding possible legal action against the Israeli leader and whether the mayor would direct the NYPD to arrest Netanyahu if attorneys determined the city had legal authority. The mayor's office did not immediately respond, however.Meanwhile, Fetterman has emerged as one of Israel's most outspoken defenders in Congress, simultaneously acting as one of Mamdani's — and the progressive left's — greatest internal party critics.Speaking to Fox News' Maria Bartiromo, Fetterman discussed his bond over Israel with late South Carolina Republican Sen. Lindsey Graham and why he would reconsider his position in the Democratic Party should its official platform adopt anti-Israel terms."That would force me to kind of reevaluate should I remain as a Democrat," he shared, later adding, "If we became the kind of party that would embrace someone like Hasan Piker, maybe my party doesn't want like a reasonable common sense kind of Democrat that reminds people that standing with Israel... used to be part of our core values and one of the reasons why I've been I'm proud to be a Democrat."